code: def layer_from_shape(self):
      from lasagne.layers.input import InputLayer
      from lasagne.layers.base import MergeLayer
  
      return MergeLayer(
          [(None, 20), Mock(InputLayer((None,)), output_shape=(None,))]
      )
  
imports: from mock import Mock
  import numpy
  import pytest
  import theano
label_desc: Use image node_id 3 for calling the TestMergeLayer obj's underlying member method code with example usage: obj.layer_from_shape() and returns: MergeLayer